Overview

Chronic kidney disease (CKD) causes destruction of the kidneys. It is progressive and irreversible.

Your kidneys are an essential part of your body. They have a number of functions:

help maintain the balance of minerals and electrolytes such as calcium, sodium, and potassium

play an essential role in the production of red blood cells

maintain the delicate acid-base balance of the blood

excrete water soluble wastes from the body

If the kidneys are damaged, these functions become compromised. In their 2009 Chronic Kidney Disease Surveillance Report, the U.S. Centers for Disease Control found that an estimated twenty-six million Americans have CKD.

What Causes Chronic Kidney Disease?

The most common causes of CKD are high blood pressure and diabetes.

Each kidney contains about one million tiny filtering units called nephrons. Any disease that injures or scars these filtering units can cause kidney disease. Diabetes and high blood pressure can both damage the nephrons.

High blood pressure can also damage the blood vessels of the kidneys, heart, and brain. This is key, because, in general, blood vessel diseases are dangerous to the kidneys. The kidneys are very vascular—meaning they contain lots of blood vessels.

Autoimmune diseases such as lupus can damage blood vessels and can make antibodies against kidney tissue.

Other causes of CKD are varied. Polycystic kidney disease is a hereditary cause of CKD. Glomerulonephritis can be caused by lupus. It can also appear after a streptococcal infection.

Risk Factors for Chronic Kidney Disease

The risk of CKD increases over the age of 65. It runs in families. It is more likely to occur in African-Americans, American Indians, and Asian Americans. Other risk factors for CKD include:

Recognizing the Symptoms of Chronic Kidney Disease

CKD does not cause any symptoms until about 90 percent of the kidney has been destroyed.

Once the kidney is severely damaged, symptoms of CKD could include:

swelling around the eyes (periorbital edema)

swelling of the legs (pedal edema)

fatigue

shortness of breath

nausea

vomiting, especially in the morning and after eating

urine-like odor to the breath

bone pain

abnormally dark or light skin

ashen cast to skin (uremic frost)

drowsiness

mental cloudiness

numbness in the hands and feet

restless leg syndrome

brittle hair and nails

itching

weight loss

loss of muscle mass

muscle twitching and cramps

easy bruising and bleeding

blood in stools

hiccups

excessive thirst

low level of interest in sex, impotence

insomnia

sleep apnea

You may also experience the symptoms of any diseases contributing to your kidney problems.

Diagnosis of Chronic Kidney Disease

The diagnosis of CKD begins with a medical history. A family history of kidney failure can raise suspicions. So can a history of high blood pressure or diabetes. However, other tests are needed to confirm a CKD diagnosis.

Complete Blood Count

A complete blood count (CBC) can show anemia. Kidneys produce erythropoietin. This is the hormone that stimulates the bone marrow to produce red blood cells. When the kidney is severely damaged, the ability to produce erythropoietin decreases. This causes the decline in red blood cells known as anemia.

Electrolytes

CKD can affect your electrolyte levels. Potassium may be high and bicarbonate levels may be low. There may be an increase of acid in the blood.

Blood Urea Nitrogen (BUN)

BUN can be elevated when the kidney starts to fail. Normally, the kidney clears products of protein breakdown from the blood. However, after kidney damage, byproducts build up. Urea is one byproduct of protein breakdown. Urea is what gives urine its odor.

Creatinine

As kidney function declines, creatinine increases. This protein is also related to muscle mass.

Parathyroid Hormone (PTH)

The kidney and the parathyroid glands interact through the regulation of calcium and phosphorus. Changes in kidney function affect the release of PTH. This affects calcium levels throughout the body.

When the kidney progresses to end stage renal disease (ESRD), it no longer excretes sufficient phosphorus. Vitamin D synthesis is impaired. Calcium may be released from bone. Over time, this causes bones to become weak.

Renal Flow and Scan

This is an imaging study of kidney function.

Renal Ultrasound

This noninvasive test measures the kidneys and prostate. It gives information about whether an obstruction is present.

Additional tests for CKD include:

biopsy of the kidney

bone density test

abdominal computed tomography (CT) scan

abdominal magnetic resonance imaging (MRI)

Treatment of Chronic Kidney Disease

CKD is chronic and irreversible. Treatment focuses on improving the underlying disease.

Treatment can also prevent and manage complications of CKD, such as:

fluid overload

congestive heart failure

anemia

brittle bones

weight loss

electrolyte imbalance

Control of underlying problems, such as hypertension and diabetes, can slow the rate of kidney damage.

Once kidney function is reduced to 10 percent or less, symptoms become obvious. At this point, there may be a need for dialysis or a kidney transplant.

When the kidneys are clearly beginning to shut down, it is called end stage renal disease. Treatment for CKD/ ESRD includes:

smoking cessation

low-fat meals

salt restriction to control blood pressure and prevent fluid overload

protein restricted diet, with adequate calories to maintain weight

potassium restricted diet

adequate exercise

blood purification via dialysis

kidney transplantation

fluid restriction to prevent fluid overload

carbohydrate restriction, for patients with diabetes

controlling diabetes

blood pressure control

iron and vitamin supplements to manage anemia

erythropoietin injections to stimulate red blood cell production.

calcium and vitamin D supplements

phosphate binders

stool softeners for constipation

antihistamines for itching

People with CKD/ESRD may be more susceptible to infection. It is recommended that they get the following vaccinations:

pneumococcal

hepatitis B and A

influenza

H1N1 (swine flu)

Prevention of Chronic Kidney Disease

CKD cannot always be prevented. However, controlling conditions like high blood pressure and diabetes can help.